4种重金属在鱼腥草中的分布特点及其影响因素

Distribution Characteristics and Influencing Factors of Four Heavy Metals in Various Organs of Houttuynia Cordata

为了探究重金属镉(Cd)、铅(Pb)等污染的土壤中鱼腥草与Cd、锌(Zn)超富集植物间套作修复的可行性和鱼腥草的食用安全,采集南方不同市县生长的鱼腥草鲜样及其种植土壤用于分析鱼腥草各器官吸收累积Cd、Pb、Zn和铜(Cu)4种重金属的特点并研究其与土壤环境因子的相关性。研究结果表明:采样地土壤Cd、Pb、Zn和Cu的含量范围分别为0.05~1.00 mg/kg、22.91~92.88 mg/kg、43.13~470.87 mg/kg和18.50~115.10 mg/kg;鱼腥草根茎叶中Cd、Pb、Zn、Cu的浓度分别为0.02~6.71 mg/kg、0.16~31.35 mg/kg、13.94~302.92 mg/kg和5.8~118.50 mg/kg,须根中四个元素的含量远大于其他器官;须根中Cd、Cu、Zn和Pb的平均富集系数BCF(bio-concentration factor,某元素须根含量/土壤含量)分别是10.07、1.86、1.00和0.21;须根中Cd存在较大的食用安全风险。鱼腥草大部分器官的Cd、Pb、Zn含量与土壤中相应元素含量、共存元素含量、土壤总氮和土壤有机质呈较显著的正相关,而鱼腥草各器官Cu含量与多个环境因子间相关性较弱。

In order to explore the edible safety of Houttuynia cordata(HC)and the feasibility of phytoremediation of soil polluted by Cd and Pb by intercropping HC with Cd/Zn hyperaccumulator,this study collected fresh samples of HC from different cities and counties in southern China and their planting soil;Cd,Pb,Zn,and Cu content in four organs of HC were analyzed and their correla-tion with soil environmental factors was investigated.The results showed that the concentration range of Cd,Pb,Zn,and Cu in the soil of the sampling site is 0.05~1.00 mg/kg,22.91~92.88 mg/kg,43.13~470.87 mg/kg,and 18.50~115.10 mg/kg,respectively.The range content of Cd,Pb,Zn,and Cu in four organs of HC are 0.02~6.71 mg/kg,0.16~31.35 mg/kg,13.94~302.92 mg/kg,and 5.8~118.50 mg/kg,respectively.The content of four elements in fibrous roots is much higher than that in other organs;the average bio-concentration factor(BCF)of Cd,Cu,Zn,and Pb in fibrous roots are 10.07,1.86,1.00,and 0.21,Cd in fibrous roots poses a qreat risk of food sofety.The Cd,Pb,Zn contents of various organs of HC showed significant positive correlations with the corresponding element content,coexisting element content,total nitrogen and organic matter in the soil,while the Cu content of various organs of HC showed weak correlation with multiple environmental factors.